var testStr = "this is the teststr,img:http://123.12.12.5312:8080/cmbank/Resource/34232432.png,dfsdsthis is the teststr,img:http://123.12.12.5312:8080/cmbank/Resource/34232432.png,dfsds";
const regex = /http:\/\/[\d|\.|\:]*(?=\/cmbank)/g;
console.log(testStr.search(regex));
console.log(testStr.replace(regex, 'https://web.testdata.com'))